Helium entrapment in a nanostructured ferritic alloy

A nanostructured ferritic alloy was irradiated with He+ to simulate service in a nuclear reactor and to test the hypothesis that the surface of nanoclusters is a preferential nucleation site for He bubbles. Transmission electron microscopy and atom probe tomography showed direct evidence of He bubble nucleation on the surfaces of nanoclusters and Ti(N,C) precipitates, and along grain boundaries and dislocations, thereby demonstrating an alloy design approach to improve the radiation tolerance of structural steels in the extreme environments found in nuclear reactors.